1. Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method for processing a substrate. Examples of substrates to be processed include semiconductor wafers, substrates for liquid crystal displays, substrates for plasma displays, substrates for FEDs (field emission displays), substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, substrates for photomasks, ceramic substrates, substrates for solar cells, etc.
2. Description of Related Art
Japanese Patent Application Publication No. 2012-44144 discloses a method in which a substrate with a pattern formed on its front surface is supplied with a processing liquid such as a chemical and then dried. In this method, in order to dry the substrate while suppressing or preventing occurrence of pattern collapse, a chemical, pure water, a solvent, a hydrophobizing agent, and a solvent are supplied in this order to the substrate, and then, the substrate is dried. This publication describes that in a case where the front surface of the substrate is only partly hydrophobized, even when the substrate is hydrophobized and then dried, occurrence of pattern collapse cannot be suppressed.
The higher the aspect ratio of the pattern (height of the pattern/width of the pattern), the more easily pattern collapse occurs. To prevent a pattern from collapsing, there is a possible method in which the whole region of a lateral surface of the pattern is hydrophobized. However, in this method, a hydrophobizing agent needs to be sufficiently supplied up to the root of the pattern. In a case where a distance between two patterns adjacent to each other is small, an upper portion of a liquid between the two patterns is comparatively easily replaced with the hydrophobizing agent, however, it is not easy to replace a bottom portion of the liquid with the hydrophobizing agent. Therefore, to supply a hydrophobizing agent up to the root of the pattern, a supply flow rate of the hydrophobizing agent needs to be increased and a supply time of the hydrophobizing agent needs to be increased.